package com.mybook.app.utils;

import org.springframework.util.CollectionUtils;

import java.util.Arrays;

/**
 * 经纬度计算，实际地址
 */
public class LatLngUtils {
    private static double rad(double d) {
        return d * Math.PI / 180.0;
    }

    public static Double getDistance(String userCoor, String cuIdCoor) {
        if (null == userCoor || null == cuIdCoor) {
            return Double.MAX_VALUE / 2 - 1;
        }
        String[] userCoors = userCoor.split(",");
        String[] cuIdCoors = cuIdCoor.split(",");
        // 假如不符合,标准格式 lan,lng,设置最大数字
        if (null == userCoors || userCoors.length <= 1 || null == cuIdCoors || cuIdCoors.length <= 1) {
            return Double.MAX_VALUE / 2 - 1;
        }
        return getDistance(Double.valueOf(userCoors[0]), Double.valueOf(userCoors[1]), Double.valueOf(cuIdCoors[0]), Double.valueOf(cuIdCoors[1]));
    }

    public static double getDistance(double lat1, double lng1, double lat2, double lng2) {
        double EARTH_RADIUS = 6378137;
        double radLat1 = rad(lat1);
        double radLat2 = rad(lat2);
        double a = radLat1 - radLat2;
        double b = rad(lng1) - rad(lng2);
        double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2)
                + Math.cos(radLat1) * Math.cos(radLat2) * Math.pow(Math.sin(b / 2), 2)));
        s = s * EARTH_RADIUS;
        s = Math.round(s * 10000) / 10000;
        return s;
    }
}
